FIG. 10. Reactions of unformolized antigens of _Richmondena_, _Zonotrichia_, and _Molothrus_ with anti-_Richmondena_ serum. FIG. 11. Reactions of formolized antigens of _Richmondena_, _Zonotrichia_, and _Molothrus_ with anti-_Richmondena_ serum. FIG. 12. Reactions of anti-_Richmondena_ serum prepared against native antigen with antigens of _Richmondena_, _Zonotrichia_, _Carpodacus_, and _Spinus_. FIG. 13. Reactions of anti-_Richmondena_ serum prepared against formolized antigen with antigens of _Richmondena_, _Zonotrichia_, _Poephila_, _Spinus_, and _Myiarchus_.] [Illustration: FIGS. 14-17. Graphs of precipitin reactions illustrating serological relationships. For further explanation, see text, pp. 190-193. FIG. 14. Serological relationships of _Richmondena_, _Spiza_, and _Molothrus_. FIG. 15. Serological relationships of _Richmondena_, _Spiza_, and _Molothrus_. FIG. 16. Serological relationships of _Carpodacus_ with the richmondenine-emberizine-thraupid assemblage. FIG. 17. Serological relationships of _Carpodacus_ and _Spinus_ with _Richmondena_ and _Junco_.] [Illustration: FIGS. 18-21. Graphs of precipitin reactions illustrating serological relationships. For further explanation, see text, pp. 190-193. FIG. 18. Serological relationships of _Spinus_ and _Poephila_ with the richmondenines. FIG. 19. Serological relationships of _Carpodacus_ and _Spinus_ with _Richmondena_ and _Piranga_. FIG. 20. Serological relationships of _Poephila_ and Richmondena with the carduelines. FIG. 21. Serological relationships of _Richmondena_ and _Spinus_ with the estrildines.] [Illustration: FIG. 22. Two views of a model illustrating serological relationships among fringillid and related birds. For further explanation, see text, pp. 193-194. Genera Pi . . . . _Piranga_ C . . . . _Carpodacus_ Po . . . . _Poephila_ E . . . . _Estrilda_ R . . . . _Richmondena_ J . . . . _Junco_ Sn . . . . _Spinus_ M . . . . _Molothrus_ Sz . . . . _Spiza_ Pa . . . . _Passer_ Z . . . . _Zonotrichia_] [Illustration: FIG. 23. Two additional views of the model shown in fig. 22 illustrating serological relationships among fringillid and related birds. For further explanation, see text, pp. 193-194. Genera Pi . . . . _Piranga_ C . . . . _Carpodacus_ Po . . . . _Poephila_ E . . . . _Estrilda_ R . . . . _Richmondena_ J . . . . _Junco_ Sn . . . . _Spinus_ M . . . . _Molothrus_ Sz . . . . _Spiza_ Pa . . . . _Passer_ Z . . . . _Zonotrichia_]